This invention relates to a method of making animals identifiable by means of a miniature responder.
In the present state of the art in making integrated electronic circuits on a chip, it is possible to make a very small responder for automatic radio-frequency animal recognition, for example, in the form of a small tubular capsule. One example of a circuit for such a responder is described in applicant's Netherlands patent No. 176404, corresponding to U.S. Pat. No. 4,196,418.
Such responders may comprise a number which is unique for each animal (the "life number") which can be read by a special transmitter/receiver to suit requirements. After being provided with such a responder, each animal is individually identifiable, which provides great advantages for example in controlling diseases, breeding programs, guaranteed quality meat, etc.
It is of importance that the responders should not be lost or become damaged. Consequently, the place where the responder is located is of great importance. This also applies if the responder takes the form of a so-called injectate.
A responder in the form of an injectate must be permitted to be applied in a simple manner, even by (instructed) lay people, must not be lost during the entire lifetime of the animal, and must continue to operate properly. A particular requirement of injectates is that they must be recoverable in a fast and reliable manner when the animal is slaughtered to prevent it from remaining behind in meat for consumption.
In view of the above, it is difficult to find a good place for implanting a responder, and in particular a good injection site, especially in the case of larger animals such as cows, but also in pigs. An injectate is implanted shortly after birth, i.e., when the animal is still small. During growth, which may take half a year to a number of years, the animal becomes very much larger, and this growth naturally also takes place around the responder, as a result of which its location is changed. Quite often, an injectate comes to be located more deeply during growth, and accordingly becomes more difficult to find during the slaughtering process. Many injection sites have been examined, such as:
______________________________________ in the ear: advantages: *relatively slight tissue growth *no loss of valuable meat disadvantages: *injectate may easily become lost, especially in the first time after injection *injectate may be damaged by the animal's striking its ears against hard objects just behind the ear: advantages: *injection site well defined disadvantages: *profuse tissue growth; location during slaughter problematic, and hence loss of time in leg at hoof: advantages: *relatively slight tissue growth, no loss of valuable meat disadvantages: *injectate may easily be damaged *difficult to detect automatically at anus or tailroot: advantages: *no loss of valuable meat disadvantages: *profuse tissue growth, difficult to find during slaughter *difficult to detect automatically. ______________________________________
Thus all of the sites hitherto examined have specific disadvantages, especially in the case of the larger domestic animals, such as cows, but also in pigs. In addition, the preferred methods of injection in these animals is subcutaneous, because that is where muscular tissue is formed least, and hence the location of the injectate during growth is best preserved. But, especially in cows, after slaughter, the entire skin is removed as much as possible as one whole (for the leather industry).
It will be clear that during this skinning process, the injectate will either stick to the skin or remain behind in the body, or even drop away.